The Data Management and Statistics (DMS) Core constitutes the central resource for all statistical and data management needs. Data generated by each of the other cores and research projects will be transferred to the Database Component for entry and storage in an integrated SIR/DBMS data management system designed to meet all the needs of the Center with respect to cleaning, organization and retrieval of data for planned and ad hoc analyses. These activities will be carried out by a data manager and a data entry clerk working directly under the supervision of the Core director on a networked system of Pentium PCs specifically configured for data management operations. The DMS Core will continue to conduct weekly meetings with coordinators and investigators from the research projects and other cores to discuss all data-related issues, including patient accrual, data completeness, retrieval and statistical analysis. The Statistics Component will be responsible for coordinating the planning and implementation of all analyses conducted by investigators in all cores and projects. The proposed research projects have certain features in common that lend themselves to similar analytic methods, including a shred prospective cohort, collection of longitudinal data, cognitive outcomes and hypothesis regarding change over time that will be analyzed using survival analysis. The DMS Core will incorporate the estimated 2,000 subjects to be recruited in the 1999 cohort into the existing WHICAP data basing system, which now contains the original 1992 cohort. This process will be carried out so that data from the original cohort and the new cohort can not only be easily combined for planned analyzes of both groups, but also readily distinguished and separated for cohort-specific analyses. In collaboration with both groups, but also readily distinguished and separated for cohort- specific analyses. In collaboration with other cores, the DMS Core will develop programmed reports to facilitate annual follow up of members of the 1999 cohort as well as surviving members of the original cohort and will develop reports to provide the project coordinator with all information necessary to contact each subject.